XpCancelPage
cancels an in-progress print page. If the job was started with output_mode
XPGetData then the data stream to XpGetDocumentData is interrupted; no
further data for the current page is generated but data for subsequent
pages can be generated. For many page description languages, such arbitrary
interruptions may invalidate the output.

If the job was started with output_mode
XPSpool then depending on the driver and spooler implementation the entire
page may be canceled or a partial page may be generated.

If discard is
True all XPPrintNotify events with a detail field of XPEndPageNotify are
discarded before XpCancelPage returns.

For clients selecting XPPrintMask
(see XpSelectInput), the event XPPrintNotify is generated with its detail
field set to XPEndPageNotify when the X Print Server has completed XpCancelPage.

The function was not called in the proper order
with respect to the other X Print Service Extension calls; for example,
XpStartPage was called before XpStartJob or was called for a type XPDocRaw
document.